Try working for a while and see if it gives you the motivation to do the work required to get high grades. University is still education, and your academic track record does not indicate that you have the study skills or self discipline demanded by A2, let alone degree level, at this point in time. You can only ever get 4-years worth of student loans (unless you're a medic), so it's better to ensure that you start the course when you're at the right level to finish it, rather than get half way through year 2 having under-achieved up to that point, and then realising that you have no chance of going back and trying again.
Have you tried looking at a year in industry?
Also, Engineering courses generally require an A-level in Maths and/or Science. You might find it too difficult without the required knowledge, and employers might be reluctant to offer you internships (which you need for employment in engineering now)